The United States on Thursday took the grim title of the country with the most coronavirus infections and reported a record surge in unemployment as world leaders vowed $5 trillion to stave off global economic collapse.

More than 500,000 people around the world have now contracted the new coronavirus, overwhelming healthcare systems even in wealthy nations and triggering an avalanche of government-ordered lockdowns that have disrupted life for billions.

A health worker carries a body on a stretcher outside Gregorio Maranon hospital in Madrid A health worker carries a body on a stretcher outside Gregorio Maranon hospital in Madrid Photo: AFP / OSCAR DEL POZO

In the United States, more than 83,000 people have tested positive for COVID-19, edging out Italy, which has reported the most deaths, and China, where the virus was first detected in December in the metropolis of Wuhan.

The US has recorded 1,178 deaths, while the global death toll stood at 23,293.

India has imposed a 21-day lockdown India has imposed a 21-day lockdown Photo: AFP / NARINDER NANU

"We are waging war on this virus using every financial, scientific, medical, pharmaceutical and military resource, to halt its spread and protect our citizens," US President Donald Trump said.

With about 40 percent of Americans under lockdown orders, Trump urged citizens to do their part by practicing social distancing: "Stay home. Just relax, stay home."

US President Donald Trump said he would have a recommendation 'before Easter' on whether parts of the US can reopen US President Donald Trump said he would have a recommendation 'before Easter' on whether parts of the US can reopen Photo: AFP / MANDEL NGAN

With fears mounting of a global recession if not depression, leaders from the Group of 20 major economies held crisis talks by video link Thursday, pledging a "united front" to fight the outbreak -- along with an enormous financial injection.

"The virus respects no borders," the leaders said in a statement.

A worker sprays disinfectant in a cinema in the northeastern Chinese city of Shenyang A worker sprays disinfectant in a cinema in the northeastern Chinese city of Shenyang Photo: AFP / STR

"We are injecting over $5 trillion into the global economy, as part of targeted fiscal policy, economic measures, and guarantee schemes to counteract the social, economic and financial impacts of the pandemic."

They also pledged "robust" support for developing nations, where coronavirus could next take hold after ravaging China and then Europe.

Streets across India come to a standstill as its 1.3 billion people are ordered to stay indoors for three weeks in an attempt to control the coronavirus outbreak Streets across India come to a standstill as its 1.3 billion people are ordered to stay indoors for three weeks in an attempt to control the coronavirus outbreak Photo: AFPTV / Arun SANKAR

But the unity pledged by the G20 has been in short supply, with China and the United States trading barbs over their handling of the coronavirus crisis.

And Italy as well as Spain, which has the second-highest death toll, objected to a draft economic plan by the European Union which they saw as too weak.

Some politicians are concerned that the fallout from economic shutdowns could be worse than the effects of the virus itself Some politicians are concerned that the fallout from economic shutdowns could be worse than the effects of the virus itself Photo: AFP / STR

Italian Prime Minister Giuseppe Conte wants a "strong and sufficient" financial response that deploys "innovative financial instruments truly adapted to a war," his office said.

Pennsylvania Avenue, usually one of the busiest streets in Washington, has been left almost deserted Pennsylvania Avenue, usually one of the busiest streets in Washington, has been left almost deserted Photo: AFP / Eric BARADAT

Alarmed by the rapid spread of the sickness in Italy, France has taken aggressive action to stem the virus and went under lockdown on March 17.

But the 365 deaths reported Thursday was its highest in a one-day period and, alarmingly, included a 16-year-old girl -- a rare case of a young person succumbing to a virus that has devastated the elderly.

Workers wearing protective clothing disinfect a hotel as a preventive measure against the COVID-19 coronavirus in Yangon, Myanmar Workers wearing protective clothing disinfect a hotel as a preventive measure against the COVID-19 coronavirus in Yangon, Myanmar Photo: AFP / Ye Aung THU

"It is very difficult to estimate when the peak will come," French health official Jerome Salomon said. "People who are ill now were infected before the confinement began."

"Now there is less contact, people are going out less and get infected less. So we hope there will be fewer people getting sick next week and fewer people going to hospital," he told reporters.

A health worker carries a body on a stretcher outside Gregorio Maranon hospital in Madrid A health worker carries a body on a stretcher outside Gregorio Maranon hospital in Madrid Photo: AFP / OSCAR DEL POZO

With hospitals under severe strain, medical workers in Italy and Spain are making painstaking choices.

"If I've got five patients and only one bed, I have to choose who gets it," Sara Chinchilla, a pediatrician at a hospital near Madrid, told AFP.

A Spanish soldier stands next to beds set up at a temporary hospital in Barcelona A Spanish soldier stands next to beds set up at a temporary hospital in Barcelona Photo: AFP / Pau Barrena

"People are dying who could be saved but there's no space in intensive care."

In Britain, the National Health Service said London's hospitals are facing a "continuous tsunami" of seriously ill COVID-19 patients, despite a lockdown imposed this week.

Chart showing the countries where the COVID-19 cases are currently growing the fastest, as of March 25. Chart showing the countries where the COVID-19 cases are currently growing the fastest, as of March 25. Photo: AFP / John SAEKI

And in New York, the virus hotbed in the United States, authorities hope to stem infections as the city struggles to more than double the number of available hospital beds.

"Almost any scenario that is realistic will overwhelm the capacity of the current healthcare system," Governor Andrew Cuomo warned.

First responders in New York were receiving more than 6,000 calls to the 911 emergency line a day, many from people seeking virus testing.

It is "breaking records. We didn't have this many calls on 9/11," said Anthony Almojeria, a leader in the emergency medical services union, referring to the September 11, 2001 terror attacks.

The pandemic has already, and rapidly, been catastrophic to the global economy.

In the United States, the world's largest economy, the Labor Department reported that 3.3 million people applied for unemployment benefits last week -- by far the highest number ever recorded.

Job losses have swept across sectors from food services to retail to transportation, as nearly half of the country has closed to "non-essential" businesses.

"It is staggering. We are only seeing the initial numbers; they will get worse, unfortunately," New York Mayor Bill de Blasio told reporters, estimating that half a million people in the city would lose work.

But Wall Street soared for a third straight day, recouping more of this month's hefty losses, on expectations for the largest stimulus in US history.

The Senate early Thursday unanimously passed a $2 trillion package that will provide cash payouts averaging $3,400 for a family of four.

Speaker Nancy Pelosi voiced confidence that the House of Representatives would follow suit on Friday.

The global lockdown -- which also hemmed in India's huge population this week -- tightened further on Thursday as Russia announced it was grounding all international flights, while Moscow's mayor ordered the closure of cafes, shops and parks.

Tokyo's millions of citizens have been told to stay home, too, just days after the city was forced to postpone the 2020 Olympic Games for a year.

China said it was barring entry to most foreigners, fearing that imported cases were undermining its success in bringing domestic transmissions way down.

And South Africa came under a nationwide military-patrolled lockdown as its cases climbed to more than 900 -- about a third of Africa's 3,200 cases.

The impact of the virus has stretched well beyond frontline health workers, with billions trapped in their homes and facing what experts say could be lasting psychological harm.

But offering a glimmer of hope, both Italy and Spain have seen lower daily rates of new infections this week.

A study from Britain's Imperial College provided a grim prediction, saying 1.8 million people could die worldwide this year even with swift action to halt the virus.